


Mated

by Ausp_ice



Series: Submergence [3]
Category: Detroit: Become Human (Video Game)
Genre: Alternate Universe, Alternate Universe - Merpeople, Anal Sex, Bottom Connor (Detroit: Become Human), Come Inflation, Consensual Somnophilia, Human Connor (Detroit: Become Human), Implied:, Knotting, M/M, Magic, Mating Cycles/In Heat, Mer Upgraded Connor | RK900, Mute Connor (Detroit: Become Human), Non-Human Genitalia, Porn With Plot, Somnophilia, Teratophilia, Top Upgraded Connor | RK900, Trans Connor (Detroit: Become Human), Underwater Sex, Vaginal Sex, and
Language: English
Status: Completed
Published: 2021-01-26
Updated: 2021-01-26
Packaged: 2021-03-12 03:00:25
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,157
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29003364
Author URL: https://archiveofourown.org/users/Ausp_ice/pseuds/Ausp_ice
Summary: Nines brings Connor to the depths of the ocean as his mating cycle approaches.
Relationships: Connor/Upgraded Connor | RK900
Series: Submergence [3]
Series URL: https://archiveofourown.org/series/1985711
Comments: 8
Kudos: 63





	Mated

**Author's Note:**

> Ny'all can thank [Frost](https://twitter.com/gildedfrost) for the prompt that inspired this
> 
> My apologies for extremely unscientific sex but *shoves under rug* let's not worry about that, shall we? let me indulge  
> If there's anything fishy (heh) going on, just say it was taken care of by  
> ✧・ﾟ:* Magic *:・ﾟ✧

Nines has been acting different lately. Antsier, touchier. Whenever they curl among the rocks to sleep, Nines would almost completely ensconce Connor in his arms and tail. 

More than that, though—it took a bit for Connor to notice, but it almost seems like… Nines is taking him somewhere. Moving with a purpose rather than wandering aimlessly, as they have been. 

_Where are we going?_ Connor signs to him in question one day, when the sunlight pierced deep enough to cast them in dim forms. Not that Nines has a problem with the dark. And Connor's night vision has been improving as well. 

Nines makes a few clicking sounds, reverberating in the ocean. Then he lifts his hands to sign as well: _home._

That was all. Connor doesn't get the chance to ask more before Nines pulls Connor's back against his chest and speeds forward—towards the darkness, towards the depths of the sea. 

Connor surrenders himself to the situation. And, well… he likes this position, anyways. He can feel Nines's muscles straining against his back, and he can watch as the ocean scenery rushes by. 

Before long, darkness swallows them. Were it not for Nines's bioluminescence, Connor might as well be floating in an empty void. He swallows and grips the back of Nines's arms where they're wrapped around him, and Nines gives a soft chirr, tightening his grip. 

Connor has no sense of how long they're in complete darkness. But eventually—there starts to be little lights like stars, floating in the ocean around them. Then glowing flora, scattered across stone and sand below them. Or maybe fauna. It's hard to tell sometimes. 

The bioluminescent plants around them grow larger, all in different shapes and colors. It's… beautiful. Connor's tempted to reach out and touch them as they swim by, but he probably shouldn't in case any are dangerous. 

Eventually, far in the distance, Connor sees a blurry, bright form. Almost like a moon or the sun, but that's impossible, right? Connor has no sense of depth, but they must be in some incredibly deep part of the sea. He can feel that it's cold, but thanks to whatever Nines has done to him, he doesn't feel discomfort from it. 

He's taken by surprise when Nines stops in a heavily rocky area. He starts swimming in circles—looking around? He probably finds what it is he's looking for, since he swims towards a small, faintly glowing opening among the stone, which turns out to be the entrance of a fairly spacious cave filled with brightly bioluminescent plants of strange sorts. 

There's something that looks like… spongy seaweed? that glows a tealish color, and a huge bulbous plant surrounded by countless filaments, glowing blue. The bulb is smooth and even bigger than Connor, with a shape like a sphere pressed flat into a still-hefty disc. There are smaller plants similar to it in various clusters nearby, only the bulbs are on swaying stems and the bulbs range from the size of Connor's head to the size of his fist.

Nines lets go of Connor and approaches the bulbous plant, pressing his hard against the bulb, which depresses as he pushes down; it almost looks like a red blood cell, except huge. He clicks a few times before pressuring his claws into it. Surprisingly, his claws don't pierce through—Connor wonders what it's made of. 

Then he turns to the other plants, a contemplative expression on his face. As much as Connor can tell with Nines shifted completely into his mer appearance. 

He seems satisfied with whatever he's inspecting, so he turns back to where Connor is floating around and beckons him closer. 

Connor obeys, swimming closer with his weak noodle arms, and then Nines takes him by the waist and lays him down on the flattened bulb. 

Huh, it's very nice-feeling. Connor rubs his hand against it, and it's pleasantly smooth to the touch. And also slightly warm. He could totally sleep here—it's the closest thing he's had to a bed in ages. 

Wait. Connor looks up at Nines, who is already starting to pull away. He grabs Nines's shoulder before signing, _What's all this about?_

Nines hisses softly, fins around his face flaring slightly. He lets go of Connor's waist to sign back, _We must prepare._

Prepare? _For what?_ Connor asks. 

Nines hesitates, glowing eyes flicking off to the side and back to Connor again. _Soon I will be… indisposed._

Connor tilts his head, bemused. _Stop beating around the bush, please._

Nines blinks. He smiles, all sharp teeth, nuzzling against Connor's face. Even without saying it, Connor thinks it's Nines's way of saying, _This is why I love you._

Then he pulls back and starts explaining. 

_My mating cycle is approaching,_ he signs. _Before, I was in captivity, and before that, I had no mate. Now we are free in the ocean, and I was able to find a proper burrow close to… Home._ He ducks his head, bioluminescence flaring slightly. Maybe it's like he's blushing. 

That's so cute. 

_That is to say,_ Nines continues, _this will be a particularly intense cycle for me. I must find you sustenance to last a week. Luckily, you have our kind's regeneration among other things, but I do not doubt that I may harm you in my roughness. Nothing too severe, but I will not be able to restrain myself._

Oh. Oh. _Oh._ Connor feels a heat rise in him, a blush coupled with a growing arousal.

Nines looks up at him. A pause, and then… _Is that… alright?_

A full week of intense sex sounds like a lot, but Connor can't say it doesn't sound exciting. _More than alright,_ Connor signs. _I told you, didn't I? I'm yours. Your_ _mate._

Nines's eyes flutter, luminescence flaring. _And I, yours._

* * *

The next few days—Connor thinks, there's no way to tell time here besides the number of times they sleep together on the strange plant-bed, Nines curled possessively around him—consist of Nines hunting for himself and gathering for Connor. Raw, glowing seaweed and other mysterious plants make for an interesting meal, but Connor can't say it isn't filling. 

Connor joins Nines when he's gathering, with Nines explaining what is and isn't safe to touch or eat, but he leaves Nines alone for his hunts. There's no way for Connor to keep up, and the thought of watching something die makes him queasy. 

Though Nines _is_ beautiful on the hunt. Luminescence muted, a dark, lethal arrow to unsuspecting prey… quite a sight. 

Nines prepares a stash of seaweed and other plants, placed in a recess on the cavern floor and covered by a stone to keep them from drifting away. 

As the days go by, Nines becomes noticeably more antsy. Twitchy. More sparse in his signs, more frequent in his hunts. And then— 

Nines shoves a glowing plant into Connor's hands. _Prepare yourself,_ he commands. _Will hunt once more. After, we start._

Then he disappears through the cavern exit before Connor can do little more than blink. 

Well, alright then. 

He inspects the plant in his hands. It looks like some leafy thing torn of a larger plant, the exposed part leaking a viscous sap. Connor lets it slowly drip onto his hands, finding that it's… very slick. 

Oh. Well, that's nice of him. Usually Connor would just use Nines's slick. But considering that he mentioned that he wouldn't be able to restrain himself… right. 

He takes off his clothes, a dress shirt and pants that he's surprised have lasted so long, placing them under a rock before returning to the plant-bed with the leaf in hand.

He tries crushing the leaf, and it expels more of the sap. He gathers it on his fingers before reaching back and inserting a finger inside himself. He takes his time to adjust to the intrusion before he inserts another, scissoring his fingers to stretch himself. Then a third, pressing deep, and he exhales shakily as he feels the muted pleasure. 

Connor turns himself to his back, pulling his legs up and using his other hand to squeeze more sap over his hole. With that he inserts a fourth finger, and the stretch burns. Still, better now than later. He closes his eyes and pumps his fingers in and out, going deeper every time, acclimating to the stretch, and then— 

He hears something in the water at the same time a light starts to shine behind his eyelids, and he opens his eyes to see Nines by the cave entrance, bioluminescence the brightest Connor's ever seen. His fins are flared wide, and his slit is engorged, already leaking with slick. 

Connor pulls his hand out of himself and opens his arms wide. In moments, Nines is on him, pinning his arms down, nuzzling against Connor's neck. A bolt of arousal goes through him as Nines nips his ear, shifting his hands down to Connor's waist. 

Then Nines is hissing, rutting against him, rubbing his slit against Connor's front, and Connor can feel as Nines's heated length starts to emerge. Due to their position, it rubs against Connor's front entrance, and Connor half-worries that Nines will go for that first—even though Connor had asked to start with the other. 

His worries are unfounded, though. Nines straightens and lifts up Connor's legs. He can see the brilliant glow of Nines's cock—huge, ridged, and brightly glowing. Connor swallows, widening his legs as Nines teases against his stretched entrance—and then he shoves himself in mercilessly. 

Connor screams—or he would if he could, but only bubbles escape from him. Nines immediately shifts his grip to Connor's hips and uses the grip to start pounding into him as if possessed, every ridge catching on Connor's rim and driving him to some purgatory of pleasure, even as the intensity burns, even as Nines has not a single ounce of the gentleness he always gives Connor. 

Connor's chest heaves with desperate breaths taken through his gills, and his hands scrabble uselessly on the plant-bed until Nines leans in and wraps his arms tightly around him, at which point Connor clings to Nines's scaled back. 

He shakes with the force of Nines's every thrust, stretching him wide, piercing him deep, so deep that Connor thinks he can feel Nines in his throat. His eyes burn, and he knows he is crying even though the sea swallows his every tear. 

Then Nines is biting down on his shoulder, claws breaking skin on his back. With one forceful thrust, Nines locks himself in Connor as his knot swells, and Connor feels the pleasure crash over him, erasing thoughts from his mind. 

When he refocuses on reality, Nines is still rocking into him, pressing even deeper. Connor shakes with the aftershocks of pleasure and pain, though by now his wounds have all healed. Nines has his face pressed in the crook of Connor's neck, and Connor turns his head to pepper kisses on the fins, on his temple, wherever he can reach. 

Nines chitters, moving one hand to Connor's head, running fingers gently through the strands. He lifts his head up to press his forehead against Connor's, and the way he looks into Connor's eyes makes him shiver, makes his heart fill with so much warmth and love. 

He wishes he could say it out loud. _I love you. I love you so much._ But the best he can do is touch his heart and touch Nines's. Hearts together. 

Nines's eyes shutter, a second translucent eyelid sliding sideways as he does. Then he presses his lips against Connor's, and if Connor still needed his mouth for breath, he knows Nines would have stolen his air away. While the skin on Nines's face and mouth are smooth, there's still a bony hardness to it—not to mention the array of sharp teeth that nick Connor's lips as Nines kisses him desperately. 

It's nearly enough to distract him from the feeling of Nines sliding out of him, accompanied by a gush of liquid that is so _warm_ compared to the cold ocean. He gasps silently and Nines plunges his tongue inside Connor's mouth, taking, taking, even as he ruts aimlessly between Connor's legs, spreading viscous slick and come all over him. 

It's overwhelming, this feeling. Nines is so much stronger than him, and Connor knows he is completely at the mer's mercy, but he still has enough sense of mind to reach down and guide Nines's cock into his now-aching front entrance. 

Nines growls, and his hips stutter only a moment, testing Connor's entrance, before he plunges inside completely. 

Connor arches his back as he's stretched so suddenly, so harshly, but he doesn't have time to adjust before Nines is pulling out and pounding in again, tail twisting wildly behind him. Nines releases his mouth and instead bites down on Connor's shoulder, hard enough to pierce, and Connor writhes from the sheer intensity of sensation. 

Connor is dizzied by the pleasure, by the pain, by the burn of being fucked so roughly, by the thought of Nines making Connor his in such a carnal way. He wraps his arms around Nines's back, hanging on for dear life as hotness fills him yet again, and the sensation is enough to send him over the edge once more. 

This time, Nines seems calmer. He wraps Connor up in his arms and curls his tail around them before licking Connor's face with a long, black tongue. Multiple times. As if he's being groomed? Huh. Connor lets Nines at it, closing his eyes and basking in the feeling of being held and filled, even while warmth drips out of his unoccupied hole. 

Nines eventually stops, reaching up to start petting Connor's hair instead. It feels very nice. Very… very nice. 

Before he knows it, he falls asleep. And then they next thing he knows is that his chest is pressed against the smooth surface of the plant-bed, and that Nines is already thrusting into his hole from behind. 

Connor jerks in surprise and pleasure, scrabbling for purchase on the smooth plant on instinct, but Nines only growls and presses down on his back, removing any possibility of him getting up. 

He can only let out soundless moans, digging fingers into the unyielding surface of the plant as he's pounded into again and again. And then Nines slams in, the familiar feeling of the knot locking then together as heat fills him, making Connor heave with voiceless gasps. 

Nines wraps an arm around Connor's chest, pulling them to their sides before his other hand slides to Connor's belly. Connor looks down without thinking too much about it, the confusion of just waking up still bleeding from his mind, and the sight is enough to make him hot all over. 

His belly glows with Nines's dick and come inside him, and between his legs is a mess of glowing blue fluids, viscous enough to last in the water. The fluids are also gathered in the dips of their plant-bed, and Connor is literally lying in a pool of it. Nines rubs Connor's belly gently, nuzzling against Connor's neck, and for a brief, nearly-hysterical moment, Connor wonders if it's actually possible for Nines to get him pregnant. 

(It isn't—even if humans and merfolk could conceive hybrids, Connor had the procedure done ages ago. He doesn't regret it, even now.)

As soon as Connor's heart stops pounding, he realizes that he's a bit hungry. Nines had told him that he'd probably need to get the food himself, and neither of them need to eat frequently, but he's not sure he'll get the chance with Nines on him all the time. 

He tries to get up, but Nines growls and holds him tighter. 

Alright then. He's not sure how far he would've gotten with Nines stuck in him, anyway. Still, he tries signing, _Food?_ where he hopes Nines can see. 

No response for a few seconds. Then Nines tightens his grip, and then they're moving towards the stash together. It isn't far—Connor could probably reach it from the edge of the bed—but moving the rock and putting it back isn't trivial. 

Nines moves just close enough that Connor can get a good grip on the rock, grab a few pieces of glowing seaweed, and put the rock back. Nines immediately pulls them back to the bed, curling around them as Connor munches on the food. It's kind of sweet and kind of salty, with a chewy kind of texture. Certainly interesting. 

Once he finishes, he snuggles back against Nines, turning his head as best he can to kiss Nines on the temple. 

This isn't so bad, he thinks. He can probably handle this.

* * *

He thought wrong. 

If he thought Nines was rough on the first day, by the fourth? fifth? sixth? Connor could barely stay awake even as Nines fucks him so roughly he's worried about ever walking again. 

In the entirety of the time since they started, Connor thinks he hasn't spent more than a few minutes with Nines's dick out of him. Either he's being fucked or he's being knotted, or he's too tired and fucked out after Nines comes in him so he conks out with Nines still inside him. Then he wakes up when Nines is rutting into him again, on his back or his front or his side, and he's rapidly losing the energy and willpower to keep himself fed or do anything but drown in ecstasy.

He's almost sure that if he didn't have Nines's mer magic doing wonders on him, he'd be a goner. Though, what a way to go. Pleasure shoots through him at every waking moment, and he's practically lit up like a glowstick with so much of Nines's cum stuffed inside him. He almost thinks he's swelling with it, in the hazy movements of wakefulness where Nines's touch is gentle and loving. Often roving over his belly or petting his hair, or other touches Connor doesn't have the energy to place but enjoys anyway. 

There is nothing but Nines, Nines and the pleasure and pain and love. Connor loses himself in it. But it's been so long since they've communicated in anything more than touch, and Connor is aching to be able to speak, to know what's going through Nines's head. But he is so tired, too tired to sign. 

And then—one moment, while Nines is pounding into his raw and overstimulated hole, something shifts. Connor is meeting Nines's gaze, exhausted, vision blurry, aching all over as he shakes with every thrust, when there's a strange hum in him, something he can't place the source of. 

He feels—arousal and love and aching need, and Nines hisses before adjusting his grip and pounding into Connor desperately. Connor's hazy awareness is chased away as another orgasm is ripped from him and Nines knots Connor once more. 

Then there is _love, love, mine. My mate. Mine, mine, mine._ Not so much in words as in feelings, and Connor takes far too long to realize that those feelings aren't his. 

There is a brief spark of awareness, and then— _touching. Our minds. Together. Love love love—_

And Connor is crying from an emotion he can't name, gasping as overwhelming love fills him and he can't tell whether it's from himself or Nines, just that it _is._

* * *

The rest is a confused haze that Connor can barely recall. But he remembers the cycles of burning need and endless love, he remembers that when exhausted hunger bleeds through his mind, glowing seaweed would be fed to him, a hand on his mouth guiding him to chew when he started drifting off halfway through eating. 

Eventually, it ends. He wakes up sore, exhausted, and achingly empty of Nines's cock, though still glowing from the come inside him. He's too tired to move. 

_Awake?_

He lets his eyes slide shut. He feels a warmth wrapped around him shift, rolling him to his back. He slides his eyes open to meet a Nines's worried gaze, recognizable as such despite the non-human features. 

_Okay?_

_Tired,_ Connor responds without putting much thought into it, but Nines seems to hear. 

Nines frowns, cradling his face for a moment before letting go and pulling away. 

Immediately, a strange, irrational panic sets into Connor's nerves, but he's too slow to grab at Nines. _Where is he going?_

Nines is back within moments, though, more mysterious glowing seaweed in his hands. He quickly reaches forward to pet Connor's hair, chirring as he reassures, _I am here, my mate. I am here. But you must eat._

Connor's panic eases away, and he lets Nines cradle him close as he feeds Connor the seaweed. Once he finishes, Nines presses his forehead against Connor's temple. _Rest._

He obeys. 

* * *

Connor can barely move for the rest of day, and he aches for nearly a week after. More noticeably, he _glows_ for that entire week and longer, and he wonders if there's something else at work here because there's no way that Nines's come can stay in him that long. He thinks. 

Nines nurses him back to full strength. Apologetic, sometimes, but Connor is quick to assure him that he regrets nothing. And how wonderful it is that he can tell Nines that with his mind now? Apparently, it's something that can occur during the mating cycle of Nines's kind, though typically not the first round. _Apparently,_ it's also why Connor suddenly gets so panicky whenever Nines is no longer holding him, but that effect fades fairly quickly over a few days. 

Once Connor feels like he's not as weak as a newborn lamb anymore, he asks, _You said this is your home, right?_

 _Near,_ Nines answers. They're curled together, Nines's chest against Connor's back, atop a large stone smoothed by the ocean. They're facing the distant light that looks like the moon. _That,_ Nines focuses on the light, _is the center of Home._

They've spent the time familiarizing each other with their thoughts, though they still communicate more with meaning than with words. So Connor can detect the strange emphasis on "Home." Interesting.

_Are there more like you?_

Nines tightens his grip around Connor's waist just slightly. _Yes,_ he returns, and faint impressions of other glittering scales and luminescent forms flicker through his mind. 

Connor wonders, suddenly, about Nines's family. His friends. His home. How long has it been? 

_Years,_ Nines tells him. _Years since I left, though they told me not to go. But I had to. I wondered._

_About what?_

Hesitation. Then, a memory, blooming across Connor's mind. A human child, the memory of the form blurred by time. It must have fallen in the storm, and Nines had wandered near the ocean surface on a whim that day. 

It must have been dying, ocean already flooding its lungs. But Nines knew magic, knew what he could do by some strange instinct. He swam towards the child and carefully gouged neat lines on its neck, feeling the magic in him flood out. 

The child breathed, but not through its lungs. Through the bleeding cuts on its neck, transformed into functional gills, if only temporarily. 

Then Nines brought it to shore, close enough to drift onto the sand. The magic faded as soon as the child broke free of the surface, coughing out seawater and taking its first breath in who knows how long before falling still. 

More humans came then, and Nines fled. 

But he wondered, returned, and eventually found— 

_Me,_ Connor realizes, the shock of the knowledge shaking him to the core. _It was you?_

He doesn't remember much about that day. But he knows it was the day he got the scars on his neck and lost his voice. And somewhere he knew it was the day he almost died. 

Silas had bawled his eyes out then. As much as they butted heads… 

Connor wonders distantly how he's doing now. 

_Yes,_ Nines answers Connor, interrupting his musings. _I didn't realize it was you at first, but my kind only rarely venture out, and when I saw the scars… I was nearly certain. My curiosity regarding your fate was satisfied at last, yet another was already growing._

Another… what?

_My curiosity about you._

Oh. 

Nines nuzzles against Connor's neck. _I am glad to have indulged in my interest. For all the pain it brought, I am happy you are now mine._

Connor turns in Nines's grip, wrapping his arms around him. _I'm glad to be with you too,_ he says. Even though he's had to leave everything behind. Eli, Silas, the life he had before. 

_One day, we can go back._

_One day,_ Connor agrees. _But not while they're still on edge, looking for you. For now… will you show me your Home?_

Nines clicks softly. _Yes._

And so they go, swimming towards the light with Connor tucked against Nines's chest. 

**Author's Note:**

> I hope you all enjoyed! it was probably inevitable that psychic shenanigans would happen fdfdfdfdff
> 
> There is.... some plot happening. There is a story going on, at least  
> I just don't want to write it out kjfsdfgh brief oneshots only and I'll let you all imagine the rest
> 
> Art is on [Twitter](https://twitter.com/Au_spice/status/1354107337951174657?s=20).
> 
> Check me out on social media: [](https://www.deviantart.com/ausp-ice) | [](https://ausp-ice.tumblr.com) | [](https://twitter.com/Ausp_ice) / [NSFW](https://twitter.com/Au_spice) | [](https://www.instagram.com/ausp.icium)
> 
> I'm also in [Detroit: New ERA](https://discord.gg/GqvNzUm) server! I have my own channel if you'd like to yell at me or just talk.


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